There is known a fuel pump that includes an impeller, which is rotatable in a pump chamber, and a motor, which generates a drive force to rotate the impeller. The fuel pump pumps fuel of a fuel tank to an internal combustion engine through rotation of the impeller. For example, the fuel pump recited in the Patent Literature 1 uses a brushed motor. A cross section of one end portion of a shaft of a rotor is configured into a D-shape to join the one end portion of the shaft to the impeller in a manner that enables transmission of rotation therebetween. In the rotor, which has the one end portion configured into the D-shape, a dynamic balance of the rotor is corrected through a cutting process for cutting corresponding part of a rotor core.
Lately, due to the implementation of the high performance of the permanent magnet through use of a rare-earth magnet, such as a neodymium magnet, use of a brushless motor in place of the brushed motor as the motor of the fuel pump has been proposed. In a case where the rotor of the brushless motor is of a permanent magnet type, there is used a bonded magnet, which is formed by resin having magnetic powder held in the resin, or a magnet, which is formed by coating a sintered magnetic body with resin.
However, in the case where the rotor core is cut to correct the dynamic balance, a magnetic part of the permanent magnet is externally exposed to cause deterioration in a fuel resistance performance of the rotor.